1. Field
The present disclosure relates to a method and apparatus for evaluating the health of complex systems and, in particular, to using spectrographic images to evaluate the health of complex mechanical systems that are subject to vibration.
2. Background
Health monitoring systems may be used for monitoring the health of various types of systems. Monitoring the health of a system may include, for example, recording sensor data that has been generated for the system, analyzing the sensor data, assessing the health of the system based on the analysis of the sensor data, managing the health of the system based on the assessment, and/or other suitable operations.
As used herein, the term “health” of a given system is defined as an assessment of the operational parameters of the given system with respect to either an ideal system having similar characteristics or a standard system having similar characteristics. A system may be “healthy” when the given system operates within one or more specified tolerances of the operational parameters of the ideal or standard system. For example, if a given automobile engine is operating within one or more specified tolerances of the operational parameters of an ideal or standardized automobile engine having similar characteristics, then the given automobile engine may be characterized as “healthy”.
The different types of systems that may be monitored may include, for example, without limitation, manufacturing systems, control systems, communication systems, satellite systems, propulsion systems, vehicles, and/or other suitable types of systems. For example, health monitoring systems may be used in evaluating and managing the health of vehicles, such as automobiles, aircraft, spacecraft, rotorcraft, watercraft, and other types of vehicles.
As one illustrative example, an integrated vehicle health management (IVHM) system may be used to evaluate and manage the health of a rotorcraft. A rotorcraft may be, for example, a helicopter. However, other types of rotorcraft exist. Rotorcraft may include multitudinous integrated moving components that are designed to operate together for a common purpose. For example, the nose gearbox assembly that connects the engine transmission of the helicopter transfers energy to a vast number of moving and interacting gears, shafts, and possibly other components. In some cases, it may be advantageous to monitor the health of this gear assembly, of other components of the helicopter, or possibly of the rotorcraft as a whole.
Currently-used integrated vehicle health management practices for managing the health of a rotorcraft may include, for example, processing sensor data generated about the rotorcraft, performing statistical analysis of the sensor data, and/or performing other operations. Further, these practices may require that the operator performing the analysis for the rotorcraft have an understanding of a physics-based model of the rotorcraft and/or the statistical approach used to analyze the sensor data.
Oftentimes, when evaluating the health of a vehicle, such as a rotorcraft, a health monitoring system may generate indications when components in the vehicle are identified as having an undesired health status. However, with currently-available health monitoring systems, indications are oftentimes generated when the components do not actually have the undesired health status. These indications may be referred to as “false positives”.
For example, a health monitoring system may generate an indication that a part on a rotorcraft needs further maintenance. However, this part may not actually need any further maintenance. In other words, the health monitoring system may generate a false positive for the part. False positives may increase the cost, time, and/or effort needed in performing maintenance for the rotorcraft. For example, inspections, repairs, replacements, and/or other operations may be performed for the part when these operations are not actually needed.
Therefore, it would be advantageous to have a method and apparatus that takes into account at least some of the issues discussed above, as well as possibly other issues.